We are looking for three outstanding candidates for PhD positions at the Anton Pannekoek Institute for Astronomy at the University of Amsterdam.
Pebbles are the critical ingredient of all current planet formation models. Pebbles are large, compacted dust aggregates that are supposed to form early on in protoplanetary disks, and huge amounts of them with very specific properties are needed. All current models simply assume they exist with maximum abundance. Do they really exist? How are they made? Do they have the properties needed to actually jump-start and accelerate planet formation?
The ERC project GT4Pebbles (Ground Truth for Pebbles) will answer these questions with a program of rigorous dust aggregation modeling, based on the results of a new and revolutionary experiment. We are building the experiment with our partner Prof. Jürgen Blum at the Technische Universität Braunschweig (Germany), the leading laboratory for this type os studies. This job advertisement is for three PhD positions at the University of Amsterdam, to do the advanced modeling. Each PhD student will work in close collaboration with the other students in the group, and with the laboratory group in Braunschweig, from where we will get the input of physical properties needed in the modeling. Become part of an exciting, interdisciplinary, international team (https://gt4pebbles.eu) that is tackling one of the most important questions in planet formation.
If you would like to work on GT4Pebbles, please indicate this in your cover letter, including an intended starting date.
The three projects are:
PhD Position 1: A collisional model for dust aggregates, based on continuum mechanics.
PhD Position 2: Dust Aggregation with full treatment of Porosity, Mass, and Compaction.
PhD Position 3: Interaction of Light with Large Porous Dust Aggregates and the Link to Observations.
For a description of the positions follow this link .
For information about the timeline and process, follow this link.
For more general information about the positions and in order to apply, go to this link .

Credit: Dominik.

On October 1st, the ERC AdG project GT4Pebbles started officially. Carsten Dominik and Jürgen Blum meet in a hotel lobby in Leiden, to celebrate and update each other.

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The discovery of exoplanetary systems has triggered a boost in the development of planet formation models. Most of these models rely on the presence of so-called pebbles – dust aggregates that have grown and been compacted in just the right way to be dynamically loosely coupled to the gas in the planet-forming disk. Only then do they enable key processes that produce planetary seeds and grow them efficiently into planets, overcoming growth barriers and enormous time scale problems. The models require that conversion of micron-sized dust particles into pebbles is global, efficient and fast. However, this is currently an unproven assumption that renders base assumptions of these models as shaky. GT4Pebbles will answer the following questions: - Do pebbles with useful properties for planet formation actually form, and with sufficient abundance? - What are the quantitative properties of these pebbles, and the consequences for planet formation models, disk observations and disk mass measurements? Building upon my recent advances in modeling and disk observations, and on advances in experimental technology in our partner laboratory, we will develop the first full-size range fractal dust-agglomeration experiment. We will gain comprehensive insights into the formation and properties of dust aggregates without relying on extreme extrapolations. By integrating experimental results with advanced numerical models, we will derive the structural, mechanical and optical properties of these aggregates as they evolve into pebbles. We will create a robust global dust growth model that for the first time meticulously accounts for porosity and compaction phenomena. This research will enable us to identify and characterize the initial seeds crucial for planet formation models in disks, providing valuable contributions to our understanding of planetary-system formation. With GT4Pebbles, planet formation models will no longer be “built on sand”, but on a solid foundation.

Credit: Dominik.